By the end of 2016 US pork producers will be required to discontinue the use for growth promotion of antibiotics used in human medicine and antibiotics in classes for human medicine used for therapeutic purposes in pork production will require veterinary oversight.

The Canadian pharmaceutical industry has moved to voluntarily end antibiotic use for growth promotion over those same time lines.

Dr Leigh Rosengren, with Rosengren Epidemiology Consulting, says the first concern that comes to mind for producers is the issue of residues in the meat.

Dr Leigh Rosengren-Rosengren Epidemiology Consulting:

Canada does an excellent job of controlling residues.

We have many CQA programs, or Quality Assurance Programs, to limit that concern.

The concern that's driving this change right now with the growth promotion and the therapeutic purposes of drugs according to human medicine is more the antimicrobial resistance problem.

That's the concern when drugs no longer work like they have in the past.

Two key concerns for the livestock industry there, the first is that resistance will develop in the pathogens that are affecting our animals and that our drugs will no longer be effective in our herds or our flocks.

The second concern is that, if resistance should develop in a food borne pathogen, a consumer could become ill and then the treatment that the doctor prescribes might not work.

The first concern of drugs not working in our production systems is very real and a big concern and that's a lot of what's driving prudent use in the industry.

The food safety concern is certainly, it exists.

It's very difficult to measure how severe that chain is and what the benefit of the antibiotic usage relative to the risk to human medicine but it's that concern that's driving these changes.

Dr Rosengren says we can expect to see all new antimicrobials to be prescription only and more products currently available without a prescription to shift to being prescription only.